This invention relates generally to banding articles and particularly to a novel band for applying implosion protection to a cathode ray tube (CRT).
There are varied instances in the art where there is a need for a tensioned band about an article. In many instances the band must be accurately tensioned with a predetermined tension. An example of a case where a band must be applied to an article with a known tension is that of implosion protecting a CRT. A CRT includes a large evacuated glass envelope. Because the envelope is evacuated, atmospheric pressure tends to collapse, or implode, the tube resulting in a potentially hazardous condition. It has been learned that the hazard of implosion can be greatly reduced by applying a tensioned band around the envelope in the stress area which exists on the sidewall between the faceplate and the frit seal where the faceplate panel and the envelope funnel are joined.
In one method of applying a band to a CRT, the free end of the band is passed completely around the sidewall to form a loop about the sidewall. The free end of the band is overlapped by the looped band and thus lies between the looped band and the sidewall. The free end is firmly grasped by a holding device and a tensioning device pulls the other end of the band to tension the looped band around the article. After the desired tension is reached, the overlapped portion between the two ends is crimped to permanently retain the tension in the looped band. A problem frequently arises in the implosion proofing of a CRT because the free end of the band must be firmly grasped while the tensioning force is being applied. Accordingly, the holding device typically is heavy and quite bulky. Accommodation of the bulky holding device, necessitates the displacement of the band from the CRT sidewall. As a result, when the holding device is removed, the band closes against the sidewall resulting in a substantial relaxation of the band tension.
The instant invention is directed toward a novel band configuration which prevents the tensioned band from moving against the CRT sidewall when the holding device is removed.
The instant invention can be made using the invention described in Application Ser. No. 200,538 filed of even date herewith by Laurence B. Kimbrough and entitled "Holding and Notching Tool for CRT Implosion Protection" now U.S. Pat. No. 4,356,845.